port forward to your computer using port 6346. LimeWire as well as any other network/internet application (such as browsers) are only as safe as you are using it. keeping a good firewall (hardware NAT routers are usually the best) and virus protection is always a good thing.

free adware/spyware remover:

AdAware: www.lavasoft.com

free antivirus applications:

AVG: free.grisoft.com
AVAST: www.avast.com

these applications have been known and recommended to be the best available. compare that to some program like norton that costs money and does not do as good as a job as those aforementioned apps.